JPH0447809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic photographing synchronization device for a photographing device such as a slit camera or a line sensor camera.

In a photographing device such as a slit camera or a line sensor camera that photographs a moving object by scanning a photographing medium, the photograph is taken from a direction perpendicular to the direction of movement of the moving object. The film must be sent in the direction of movement of the image projected on the image at a speed that is synchronized with the image. Similarly, in a line sensor camera, the timing of image reception and scanning of the sensor, which is the imaging medium, must be synchronized. If the image is not synchronized with the moving speed, the captured image will have a different aspect ratio from the actual image. Therefore, in order to determine the scanning speed or scan timing of the photographic medium, it is first necessary to accurately know the moving speed of the object to be photographed, but even if the moving speed is known, the moving speed of the image cannot be calculated from the photographing distance and the focal length of the lens used. There must be. Conventionally, this has relied on the experience and intuition of the photographer, which has often resulted in images having different aspect ratios from the actual images.

SUMMARY OF THE INVENTION Therefore, the present invention provides an automatic photographing synchronization device that detects the moving speed of a photographic object immediately before the photographing position and synchronizes the scanning speed of the photographic medium with this speed.

An embodiment of the present invention will be described below based on the drawings. In Fig. 1, the lens 2 of the slit camera 1
The image from the screen passes through the half mirror 3, and further passes through the slit window 5 of the slit plate 4, and is transferred to the film 6.
imaged on top. Film 6 is sprocket 7,
8 in the direction of arrow a. On the other hand, the image reflected by the half mirror 3 forms an image on line sensors 9 and 10 arranged at the same distance as the film surface. 11 is a control device, and line sensors 9, 1
0, the moving speed of the object 12 between A and B is detected, and the film 6 is sent at a speed synchronized with this.

An example of the control device 11 is shown in FIG. 2, in which 13 is a line sensor scanning circuit;
4 and 15 are amplifier circuits, 16 and 17 are waveform shaping circuits, and 18 is a time detection circuit, which detects the time from the rise of the output of the waveform shaping circuit 16 to the rise of the output of the waveform shaping circuit 17. 19 is a time-voltage conversion circuit that converts this time into a driving voltage for the motor 20. 21 is a rotation speed detection circuit of the motor 20;
22 is a speed-voltage conversion circuit, and 23 is a voltage comparison circuit. 24 is a drive voltage control circuit, and conversion circuit 1
The voltage from the motor 9 is controlled by the output of the voltage comparison circuit 23 to generate a driving voltage for the motor 20. Reference numeral 25 is a switching circuit, and 26 is a passage detection circuit, which produces an output after a certain period of time has elapsed since the object to be photographed has passed through point B.

Next, the operation will be explained. When the object 12 to be photographed comes to point A in Fig. 1, the image is transferred to the half mirror 3.
is divided into A' and A'', and A'' is imaged on the line sensor 9. The line sensors 9 and 10 are scanned at regular intervals T by the output of the line sensor scanning circuit 13 shown in FIG.
from the line sensor 9 by reaching the point
The output shown in the figure is generated and supplied to the waveform shaping circuit 16 via the amplifier circuit 14 of FIG. Waveform shaping circuit 1
6 generates the pulse Pa shown in FIG. 3 and is supplied to the time detection circuit 18.

When the photographic object 12 reaches point B, the line sensor 10 generates the output shown in FIG. 3, and the waveform shaping circuit 17 generates the pulse Pb shown in FIG. The output terminal 18a of the time detection circuit 18 generates a count output of the time t from the rise of the pulse Pa to the rise of the pulse Pb. This count output has a value corresponding to the moving speed of the object 12 to be photographed, and is converted by the conversion circuit 19 into a driving voltage for the motor 20. Since the motor 20 is not rotating yet, the drive voltage is directly generated from the drive voltage control circuit 24 by the output of the voltage comparison circuit 23 and supplied to the switching circuit 25. The switching circuit 25 receives the third signal from the time detection circuit 18.
The output shown in the figure turns on from the rise of the pulse Pb. Therefore, the motor 20 is driven by the drive voltage, and the film 6 is scanned by the wheel train mechanism 27. Even if the driving voltage of the motor 20 is constant, the rotational speed of the motor 20 changes depending on the load, that is, the amount of film 6 remaining. Therefore, this rotational speed is detected by the detection circuit 21, converted to a voltage by the conversion circuit 22, and compared with the voltage from the conversion circuit 19 by the voltage comparison circuit 23. The drive voltage from the drive voltage control circuit 24 is controlled based on the comparison result, and the film 6 is scanned at a constant speed synchronized with the moving speed of the object 12 to be photographed.

Therefore, when the object 12 to be photographed reaches point c in FIG.
An image is formed on the surface and images are taken continuously. Then, in order to stop the film advance with a certain amount of time after the image finishes passing through the slit 5, the output from the line sensor 10 is stopped for a certain period of time (for example, when the object to be photographed moves from point A to point B). After the time t) required for this has elapsed, an output is generated from the passage detection circuit 26, the time detection circuit 18 is reset, and the photographing is completed. However, this margin time is not limited to t, and may be set arbitrarily, and may be stopped by operating a manual switch.

Although the above example uses a slit camera, the present invention can be similarly applied to, for example, a line sensor camera. In this case, the interval from one scan to the next scan of the imaging line sensor may be synchronized with the moving speed of the imaging target.

As described above, according to the present invention, the scanning speed of the photographing medium is automatically synchronized with the moving speed of the photographic subject, so there is no need for manual labor at all.
It is possible to capture images with the same aspect ratio as the actual subject. Since the speed of the object to be photographed is detected by the reflected light of the half mirror, and the object is photographed by the light passing through the half mirror, the structure for detecting the speed and the photographing medium are not placed in parallel in the same direction. Both can be installed separately, making the configuration compact.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the present invention, FIG. 2 is a block diagram showing an example of the circuit configuration, and FIG.
The figure is a time chart for explaining the operation. 1... Slit camera, 2... Shooting lens, 3
...Half mirror, 6...Photography medium, 9,10...
. . . first and second detection means, 11 . . . speed detection means and control means, 12 . . . object to be photographed.

Claims (1)

[Claims] 1. A photographic lens installed at a position where the optical axis is perpendicular to the moving direction of the photographic subject, a half mirror arranged at a predetermined angle with respect to the optical axis of the photographic lens, and a device that receives light transmitted through this half mirror. a photographic medium, first and second detection means for detecting the photographic subject using reflected light from the half mirror at two desired points before the photographic subject crosses the optical axis of the photographic lens; Automatic photographing synchronization comprising a speed detection means for detecting the speed of the photographing object from the output of the means, and a control means for synchronizing the feed speed of the photographing medium with the speed of the photographing object detected by the speed detecting means. Device.